Quaternary ammonium compounds



United States Patent US. Cl. 260-290 2 Claims ABSTRACT OF THE DISCLOSURE Undesirable odors in quaternary ammonium compounds are prevented by admixing up to 2% by weight of S0 and then drying said compounds of solvent.

This invention broadly relates to quaternary ammonium compounds and more particularly to a method for preventing the development of undesirable odor in quaternaries, and to the composition produced'therefrom.

Quaternaries, when prepared as a dry product, free of solvent, develop strong off-odors. The exact cause of this is not known but the problem is so bad that batches of quaternaries, such as di(hydrogenated tallow) quaternary ammonium chloride, must be completely discarded or reprocessed at considerable expense to remove offensive odors that have developed in the product since its manufacture. Obviously an offensive odorous product is not normally saleable especially for such use as household detergent, germicide and the like.

An object of this invention is to provide a novel process for quaternary ammonium compounds.

Another object is to provide an improved purification process for quaternaries which is economical.

Still another object is to provide a process for preventing the development of undesirable odor in quaternaries which is relatively easy to perform, even by unskilled technicians.

A further object is to provide a process which imparts odor stability to quaternary amines.

A still further object is to provide a purification process which leaves no undesirable residue in the finished quaternary so that it may be further processed without subsequent deleterious effect.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the composition possessing the features, properties, and the relation of constituents, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

It has now been found that quaternary ammonium compounds, during manufacture or subsequently may be stabilized against odor development thereafter by the mere addition of proper quantities of sulfur dioxide (S0 thereto. The addition is preferably performed just prior to stripping of the reaction solvent. The quaternary may then be cooled and flaked or pulverized; or even spray dried. Thereafter the quaternary will be stable to odor, and as such is ready for use as a component in compositions were odor may be crucial or as a reactant in further synthesis. The S0 has no deleterious effect upon such further use, and in fact, imparts a unique odor stability to the quaternary.

While the amount of S0 needed will vary with the particular preparation of quaternary usually up to two percent SO by weight may be used, The preferred amount is 0.1% by weight.

The invention is more thoroughly described by reference to the following examples which show not only how 3,452,028 Patented June 24, 1969 the invention may be performed but also the limits of S0 that are desirable.

In Examples I to V1, the quaternary is freed of solvent using a 200 cc. separatory funnel with ground glass connections fitted upon a fiveliter resin flask, which in turn is connected to a vacuum system. The quaternary is placed in the separatory funnel and maintained at -105 C. Vacuum is then applied to the resin flask and the molten quaternary is slowly admitted to the evacuated resin flask at such a rate that the vacuum is maintained at a relatively steady pressure of 10-2O mm. Hg. The hot molten quaternary under these conditions will rapidly lose its solvent and fall to the bottom of the resin flask as a dry friable powder.

EXAMPLE I In a one liter Z-necked flask equipped with means for mixing and a reflux condenser are placed 400 g. of dihydrogenated tallow dimethyl ammonium chloride such as Arquad 2HT 75% active, manufactured by Armour and and Company, Chicago, Ill. The quaternary is heated until molten and gaseous S0 is slowly bubbled in for a period of minutes. The product is then stripped of the solvent, water and isopropanol in the manner described above.

With the above amount of S0 the dried product will be found to be strong in residual S0 odor. This is obviously undesirable.

EXAMPLES II, III, IV, V

Example I is repeated, but in each of succeeding examples, the S0 is successively diminished by bubbling in decreasing periods of 20, 10, 5 and 3 minutes respectively.

However, the dried quaternary is still strong with residual S0 odor. So, further reduction is necessary.

EXAMPLE VI S0 is bubbled into a 50:50 mixture of water and isopropanol until a 2 molar S0 solution is obtained (12.8% S0 10 cc. of this mixture are then added to 100 g. and 200 g. of 75% Arquad 2HT. The quaternary is dried as previously described and checked for S0 odor. In the 100 gram sample, S0 could be detected but in the 200 gram sample, S0 is no longer detectable. Thus, the proper concentration of S0 for Arquad ZHT is determined.

PILOT PLANT EXAMPLES Quaternary S02 used Examples wt. (lbs.) (cc. of 12.8%) Comments VII- 35. O 59 Some quaternary odor still present. VIII 35. 0 100 Do. IX 35.0 100 Do.

35.0 200 Quaternary odor barely discernible. 35. 0 300 S0 odor. 35. 0 200 No quaternary odor, but

slight S0 odor. 35. O 200 Do. 35. 0 200 Do. 35.0 No quaternary or SO 2 odor. 35.0 150 Do. .35. 0 150 D0. 140. 0 600 D0. 507. 0 3280 Do. 224. 0 896 Do.

The above process is applicable to any fatty quaternary ammonium compound, such as distearyl dimethyl ammonium chloride, disoya dimethyl ammonium chloride, dicoco dimethyl ammonium chloride, cetyl trimethyl ammonium bromide, stearyl dimethyl benzyl ammonium chloride, cetyl dimethyl ethyl ammonium bromide, cetyl dimethyl benzyl ammonium chloride, cetyl pyridinium bromide, tetradecylpyridinium bromide, dodecylbenzyl trimethyl ammonium chloride and similar quaternaries.

The solvent out of which the quaternary is dried may comprise any of the customary polar solvents usually used in the syntheses of the quaternary, such as the organic alcohols, particularly ethanol, isopropanol, butanol and the like.

The S is usually dissolvable in these polar solvents, but one could also utilize a non-polar solvent for the S0 provided it were miscible with the solvent contained in the quaternary being deodorized.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the composition set forth Without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween.

What is claimed is:

1. A process for preventing the development of undesirable odor in fatty quaternary ammonium compounds comprising admixing up to 2% by Weight of S0 in the 4 presence of solvent to said quaternary ammonium compounds and then drying said compounds of solvent.

2. A process for preventing the development of undesirable odor in fatty quaternary ammonium compounds Without imparting a sulfur odor to said compounds comprising admixing about 0.1% by Weight of S0 in the presence of solvent to said quaternary ammonium compounds and then flash drying said compounds of any solvent.

References Cited UNITED STATES PATENTS 2,692,286 10/1954 Stayner 260-567.6 2,826,582 3/1958 Miller 260-290 OTHER REFERENCES Seel et al.: C. A. 5011661 (11S6).

Chemical Abstracts Subject Index, page 2529 S (664).

Cotton et al.: (Interscience, 1962), pages 226-7, 4235.

HENRY R. JILES, Primary Examiner.

C. M. SHURKO, Assistant Examiner.

US. Cl. X.R. 260567.6, 999 

